Process and apparatus for metallizing ores



May-10, 1927. 'H' N. TRACY Pnocss AND APPARATUS Fon METALLIZING omas ,Filed May 29, 1923 3 Sheets-Sheet 1 May 1o, 1927a H. N. TRACY PROCESS AND PPARATUS-FOR METLLIZING ORES Filed May 29, 1923 3 Sheets-Sheet 2 y 10 7 H. N. TRACY PROCESS AND APPARATUS FOR METALLIZING ORES Filed May 29, 1923 3 Sheets-Sheet 5 rame@ May-r 1o, '1972i 1,628,012

vUl'w-l'rl-:D STA A151s PATENT OFFICE.

- HARMON N. TRACY, OF LOS ANGELES, CALIFORNIA.

PROCESS AND APPARATUS FOR METALLIZING GRES.

Application lcd Kay `29, 1923. Serial No. 642,164.

This invention relates to the general type the gangue. .These and other objects andy of process that isset out in my application correspondingaccomplishments of the in- Serial No. '349,408 filed January 5th, 1920, vention will be best understood from the on process and apparatus for metallizingj` following detailed description of a preferred ores. The present process, like that of the Vform of apparatus and process embodying 60 prior a plicaton.' extracts metal from the the invention, reference for this purpose orcs` by ringing the metal carrying ore into being had to the ,accompanying drawings contactwith a bathof liquid and prefer? in which: ably molten metal, such a-s lead; and -main- Fig. l is a longitudinal vertical section tains on the ore and on the lliquid metal showing the major-portion of the apparatus, 65

' bath an atmosphere I.of non-oxidizing gas. parts being showninelevation;

-This process, again like the process de- Fig.,2 is a longitudinal vvertical section scribed in the prior application` .also pretof those parts of the apparatus shown in erably first reduces the metal in the ores to elevation in Fig. 1 and also of the remaining metallic state; theV reduction` action being ganguo handling portion of the apparatus:l 7 0 preferably carried on simultaneously and Fig. 3 is a longitudinal vertical section o l continuously with the metalvextracting aca -preh'eating or roasting apparatus as may tion, and an atmosphere, preferably the' housed with my system; same atmosphere, of non-'oxidizing gas being Fig. 4 is a somewhatv enlarged horizontal maintained on the ore during itsreduetion.- section on line 4-4 o f Fig. 2;

For purposes of reduction the superimposed Fig. 5 is a similar section on line 5-5 of atmosphere is maintained with a reducing Fig. 2; and gas; and so, in the practical operation ot Fig. 6 is a section taken as indicated by my process I use a reducing gas throughout line 6 6 on Fig. 4. l-

as that gas serves both as a reducing agent In the drawings I show at 20 a preheat- `and serves to supply a non-oxidizing atmosing or roast-ing drum that needs no special phere during 'the metal extracting operadescription except to say thatit isffed by tions; feeder-21 which may be controlled, for in- The improvements that are concerned parstance, by rheostat'l22, to control theamount tibularly in vthis present application relate o ore fed into it. The speed of rotation of' most tol improvements in the operations of the drum, which is operated by a motor 23, extracting the metal from the ore after the may be controlled by a rheostat v24. The metal has been reduced lto metallic state; lower end of the drum discharges into a furand, although there are many objects atnace structure 25 and discharges directly :i5 tained by the present improvements, both in into a chute or inlet 26 that carries the ore no process and in apparatus. and while the into the uppermost one of a series ot deoximajority it not all of the'objects and corredizng elements 27. These elements are spending features and advantages of the lueferably 1n the form of pipes or 'tubes invention, will be best and most fully under- Within which there are spiral conveyers, op-

stood from the following detailed descriperated by motor 28 and gearing 29, the 95 tion, I will here merelj,7 say in a prelimi'- Speed being controlled by a rheostator connary way that itis generally an object to troller 30. The spiral conveyers withinthe provide a process and apparatus in which tubes may be in the formof a continuous there is no tendency for the ore to gather spiral as illustrated at 31', or may be in the together in sticky masses-to ball up; and vform of a; broken or discontinuous spiral as 100' thus to kee the ore in finely divided conillustrated at 32: the function of the last dition at all) times `during its treatment and mentioned form being not only to feed the thus increase the efficiency of metal absorpore through the tubes 27 Y but also to keep it tion by the molten bath; and to provide a well agitated and thus caus'e it to come mto process and apparatus which attains a high thorough intimate contact with the ideoiri- 105 percentage of metal'extracton, and in which, dizing atmosphere and at the same time Aprethe gangue is easily andcleanly separated vent it v'from balling u The ore, after from the bath metal .so that a very small having been carried .bacll and forth in' theV amount of the bath metal, and therefore deogtidizing tubes, 1s finally carried out Y of theextracted metal, is carried away with tbrugh the final tube 27* to the metal exlIl.

f y tracting device. Tubes 27 are s'et in furnace structure which is heated from below by a burner to maintain a proper deoxidizingtemperature.r The initial combustion in this furnace takes place in the lower cham- `ber 25a; and the amount of heat that passes 1 into and through the chamber 25" in which the deoxidiziiig tubes are located may be controlled by dempers 36. From the upper end of chamber 25b there may be a discharge pipe or stack 3T; and the gases of combustion from chamber 25" may pass out through 37 or may wholly or partially pass, under the control of danipers 38 into the uppermost furnace chamber 25, hence theymay pass throughdrum. 2O to aid in heating the ore inthe drum. The flame from burner 35| may ofcourse b e maintained in reducing, neutral or oxidizing state as may be desired. Therev is also,fa burner providedat for the sole purpose of heating `the ore in the f drum, and for roasti l' chamber 25..

au finely it if necessary; and for this purpose air 1s admittedv at 41 in proper quantities. Also any excess reducing gas that has not been completely used up in the reducing oplerations in tubes 27', may be passed throng pipe 42 into combustion With some ores, as oiiides, it is only necessary or desirable to reheat them; while with others, as sulphi es, it is desirable to both preheatv and roast, in preparation for the deoxidizing step. The ore thus reaches' the deoxidizing tubes as oxides, or lin such form as may be reduced by reaction with a reducing gas.A The action in reducing tube 27 then becomes simply to reduce the metal to metallic state; and in this form the ore, divided, is discharged through the last tube 27a into the device that I Aterm the lead pot 50. I may say here, thatffor the purposes'of the process I explain I pre- For convenience in construction tion or repair the pot is provided with a re- I have now developed it, has a circular casing with a lower part 51 of smaller diameter and an upper part 52 of larger diameter.

movable cover 53. vertical ore-feed 54 extends down through the center o e cover to a. point near the bottom ofthe` t land there it is expanded to form a cham r 55 that eneloses the mulling disks 56' and 57.. Disk 56'is stationary while disk 57 rotates, being mounted on shaft 58 on which is` also mounted the runner 59 of ace'ntrifu al ore throwing device. These 'runners are ormed substantially the same as the centrifugal runners of a pump of whatkis known as the shrouded type. A A cover plate 60 covers the upper surface-of the runners and is'supp'orted on casing 55; and a bottomA plate61 encloses the runners below. Outside these ceuti'ifugal runners I provide reaction vanes 62,

of proper form to absorb and stop any circular motion of the materials and of the molten lead in the pot so thatthebody of lead `-is relatively quiescent and maintains a relatively quiet and smooth upper surface. The spaces between the reaction varies 62`are openl upwardly so that the materials `.thrown out into them may freely iloat upl through-the lead bath L. The. level of the lead bathis maintained constantly at the point illustrated in the drawings 'by the ex dient of having an overflow pipe 63 which discharges a small amount of lead into a small'reservoir 64. This reservoir has a level indicator-65 for the ur se of enabling the operator to keep the lea level L inreservoir 64 below the level of discharge pipe 63. From this reser- 'Y voir the lead is pumped at a.- s'uitable rate by asmall pump 66 through pe 67 back into tube 27*L where it is carri the ore passing through that ptiipe. Thus the lead level in the pot is constan y maintained at the same point. At the Sametime this constant assage-of a small portion of the bath meta and with it of course anymetal that it has absorbed, into tube 27a, assists; in the thorough admixture which I desired to ttain between the ore and the'bath metal.

This is perhaps of small orno consequence as long as the o eration in the lead pot 1tself is not carrie beyond the etlicient capacityof the lead pot;but if the capacity of the along. with Y lead pot is pushed so to' speak, then'I nd I can'still maintain the maximum etliciency by passinga suitable small portion of the bath metal continuously into the tube 27a.

Of course, the lead level inthe pot ma be ma-intaingd without passing the lead into tube 27".; and that case it is only ore, car- Aryin metal in metallic state, that is thrown out .into leadl bath by the centrifugal runners; but I prefer to do as I have described, and so the centrifugal runners throw out into the lead bath also aV small quantity ofthe bath metal itself The centrifugal runners are so shaped, and are operated at suchV speed, as to overcome the liquid ressure of the bath metal and as to throw t e ore outwai-dl against that into t e bath metal. en the device'is in full operation, Ythere isfof course no bath A metal (except the 'small amount inter-'mingled -pvhressurm and f/orciblywith and thrown out with the ore) 'presentf in the eentrifugalvanes; the ore infact coining intocontaet' with the metal bath as 1t leaves the Yanes. Theora 1 :tenacia into the metal bath; in finely divided state; and, considering any one instant or a short period-of time, in an amount comparatively small in relation to the mass of the metal enough to project into the liquidand thus f form a'liquid seal.

` independently controlled.

Around that sleeve, and spaced from it, isv another rotating sleeve 71, mounted on bearings 72, and slowly rotated (say about 3 R. P. M.) by means of gearing 73 from a shaft 74 that is driven'by some suitable means, as a motor 75. The centrifugal runner shaft v58 is also driven by some suitable means, as a motor v76. By controlling the speeds of these motors, the speeds of the various driven parts may be The rotating sleeve 71 carries a pluralityof pipes 78 provided'with erforations 79 through which the gas is directed downwardly and angularly rearwardly (that is, opposite to the direction of rotation of the parts) onto the surface L2 of liquid L. The gangue that comes to the surface infinely divided particles is blownup as dust into the space above the liquid level, and from this space the dust is carried ina gascurrent out through pipe 80 into a dust collectorl 81 that may be o any suitable kind. From this dust collector the clean gaspasses out through pipe 82 to a blower 83. The gas is then forced by blower 83 to pipe 84. This pipe 84 passes through the horizontal flue 85 and the lower portionof chamber 86 of a stack 87 for the l very high, so

leo

purpose of maintaining the gas at such a templerature that it will not cool the surface of t e molten metal in the lead pot. For this purpose the pipe 84 may discharge into a somewhat enlarged chamber 88 in llue 85; and from this heating chamber a pipe 89 leads again to the upper part of the lead pot, discharging into the lead pot at a point inside-the circular wall 90 thatkeeps this gas from immediately passing into t e open space over the .liquid and forces'it to pass into the sleeve 71 and thus into pipe 78.

The pressures used on the gas are not that the jets at 79 are just strong enough to blow up the gangue dust and not to blow up any lead Ior metal dust that may be entrapped with the gangue'dust.

And by putting the perforations 79 on the back side of pipes 78 there is less tendency of the jets to blow the material along the lead surface; in fact, the action on the heavier metal particles is to blow them down-depress them-into the lead bath. This is somewhat indicated in Fig. 6.

The circular' wall 90, in effect, forms an annular chamber' around the upper end of sleeve 71.. (')ulside the circular wall 90 there is anolherbut wider annular chamber'95; whose outer wall is formed by another annular wall 96 near the outer edge of cover 53. This ,outer wall 96 is conveniently formed with`A a downwardly extending por tion that extends down from the top -of the cover and then with a horizontal portion 96a that forms a lconvenient support for the outerends of pipes 78 then a downwardly extending flange 96 lthat terminates just above the liquid level. The dust that is blown up by the gas jets or streams from pipes 78 is blown up into the space 95 and then it is blown under the lower edge of 'flange 961 and into the annular space outside Wall 96 and with which space pipe 80 connects. Not a very high pressure is re quired ffor these operations. The gas in thisI system is used over and over again and fresh gas only needs tol be supplied to make up for casual losses. The gangue dust may be removed from dust collector 81 in any suitable manner that does not allow escape of the gas. For instance, under the lower end of the collector I may arrange a travelling conveyor belt 91 that will carry off the dust, v I

while the accumulated dust in the lower part ofthe collector prevents thegas from reaching the lower outlet of the dust collector.

Now, in order to keep the Alead surface freely reach the surface" state as to be skim'- and float'on the liquid in such removable as described, I provide a f clean and free of any scum, lso thal the A gangue' dust may ming device preferably in the form shown j in the drawings, and there may be one more of them. I showl two` for instance.'

supporting rod 100 is mounted on rotating s sleeve 71, and this rod'carries a pair of arms 102 and 103 that carry at their outer ends a skimmerba'r 104. One end of arm 102 has a stop or bumper 102 that comes up against 'part 96A to limit the downward movement of skimmer bar 104 to a position where it either just touches the liquid surface or just extends below' it far enough to skim ofi` the scummy matter that accumulates. These skimmer bars by their revolution carry the surface scum around to a small trough 105 that has a small splral conveyor, 106 in its bottom. This trough is mounted at its inner 'end,an d also communicates at Vits innerv end with the stationary ore feed pipe 54, and the spiral conveyor .106 is rotated by any suitable means. Merely for purposes of illus? tration here I show a sprocket chain connection 107 from the conveyor shaft 108 in re` ducing tube 27 driving the spiral in such a direction as to feed the and other matter into pipe 54. This trough 105 preferably has an apron 109 projecting from its edge in such a direction that the revolving gathered scum is picked upby the apron and then carried over the a ron surface into the trough. c The upper e ge of the trough .stands just above the liquid level, and the apron surfacevmay vstand substantially at the liquid level or just above it, so that it will pick up only the scum accumulation that is being moved forward by the .skimmer bars. It will be apparent from what I have said that the skimmer bars can rise over the apron and trough. 1

By this arrangement the liquid surface is not only kept free of a surface scum or other thick or tenacious film, but also the collection from the surface is put back through the muller and the centrifugal runners. The surfacel is kept clean enough so that the finely divided gangue'particles can freely pass upwardlythrough the surface and float on the surface. At the same time, any ore particles that may happen to have coalesced into larger" bodies during the passage up.

wardly through the liquid lead, and which may be so large as not to be removable by the gas current, are gathered upin the scum and fed back to the muller where they are finely divided 'and put through the lead again. Thus, any metal that 'may have escaped extraction on the first lead passage is again put'back through the molten bath in finely divided form; and any metallic particles that may have been caught in the scum are also kept inthe bath. I have found that .time to time.

during the time it takes to char e the met-al bath up to its maximum capacity with absorbed metal, the scum does not accumulate beyond the amount that can be handled in the manner herein described. That statement is made on the assumption that the lead pot mayy be operated on the batch principle and the lead with its absorbed metal entirely removed and re laced withv fresh 'lead from owever, the lead pot may be operated continuously by Cthe continuous withdrawal ofjlead amalgam and continuous introduction of fresh'lead; and in that case the accumulation of scum is kept down because the/'scum forming materials will. be withdraw rproportionately with the. Withdrawal of the lead amalgam.-

The function of mullers 56 and 57 is not to grind the ore, but is merely to disintegrate any accumulations of *the small particles into which the ore is initially ground.

' The positioning'ofy the mullers directly .ad-

jacent the centrifugal runners and so that the ore passes. directly from the muller to the centrifugal runners, insures .the ore reaching the lead bath in finely divided state and without -any substantial opportunity of "balling up. lFor this purpose the capaclty accumulated scum t9 passv into the lead ber 130 that is l'r/eated from 25 throughy the control of damper 131. i This chamber communicates with lue 85 of the muller is designed tombe considerably greater than the normal ore feed and the capacity of the centrifugal runners is also.`

much greater than the normal ore feed.

Conseqiliently, the mulled ore is dropped 7eA from e muller into the centrifugal runners in the form of finely divided particles comparatively widely separated (rather than in la solid stream). Also the runners throw out into the leadbath, along with the ore, A i

a certain quantity of the reducing, or at least non-oxidizing gas. It is preferred not to design and operate the runners at such speed that theg'will throw a body of gas out gas out into the lead bath as is entrained with the particles. vThis gas serves, to some extent at least, to make up for such loss of gas as may occur -by gas entrainment with the dust that is removed from dust collector ing operations in tubes 27l is fedin initially under pressure at a point such as illustrated rby' pipe 120, so that vthe vdeoxiclizing gas 90 passes through the tubes op sitely tothe passage of ore. This deoxl izing-gas also passes down -gliroughY pipe 54 and around the mullers 1ng) gas in the centrifugal runner. Thus, the ore has a constantly non-oxidizing atmosphere maintained -upon'it up to the instant v1t enters the bath; andthe surface ofthe molten metal around the centrifugaL runners (the surface .that the ore particles enter) also vhas this non-oxidizing atmosphere maintained upon it. Likewise, -in the manner I have hereinbefore described, the upper surface of the molten metal has a .deoxidizing tubes.r The suction side of the gas `circulating system is "thus maintained,

like the gas in the deoxidizing tubes, above fatmospheric pressure. In fact, there is a gas communication through spiral conveyor 106, between vthe space 'over the lead and the deoxidizing tubes; .andthus a sinvle Apoint 'of gas introduction the whole L may suice for apparatus.

The `liquid metal bath is maintainedat proper temperature by beingP set vin a 'chamand stack 87. y'Reservoir 64 is also set in chamber 1,30. v

The lefad amalgam ath; but they do'throw such y80 The gaseous atmosphere for the deoxidiz d thlis maintains an atmos- ,y phere of deoxidizing (or atleast non-oxidiz- 95 l urnace chamber withdrawn may be 130 treated in any suitable manner to recover the valuable material and the lead then re turned to the pot for reuse. The process is applicable to any metal that is amalgamable with a liquid. That liquid may bea-of any suitable substance for the particular metal being treated. I do not limit myself necessarily to liquid metal, nor to a metal that. is kept liquid by heat; although I have found that molten lead very ethciently extracts many`of the metals, among which are gold and silver. j.

Having described a preferred vform of my invention, I` claim: 1

1. A processfor extracting nifetal from ores that includes forcibly throwing metal carrying ore in finely7 divided form, and'with its partlcles relative y widely dispersed, into a body of metal absorbing liquid at a point below its surface, and maintaining, a nonoxidizing atmosphere on the ore and on the liquid surfacevat vthe place of entry of the ore into the liquid.

2. A process 'for extracting metal from ores that includes forcibly throwing metal carrying ore in finely divided form, and with its particles relatively widely dispersed, into a body of molten metal at a point below its gether upper surface, and maintaining a non-oxidizing atmosphere on the ore and on the liquid surface at the place of entry of the ore into the liquid.` f'

3. A process for extracting metal. from ores that 'includes forcibly introducing metal carrying' ore into a body of molten metal heavier than the ore at a point below its upper surface,` metal surface any scum accumulation towith ore that may be caught in such scum, to the ore being introduced into the body of molten metal, and removing the spent ore from the surface ofthe molten metal.

4. A process for extracting metal from ores that includes forcibly introducing metal carrying ore into a liquid heavier than low its surface, and removing from the upper surface of the liquid bod the spent ore that ioats on the surface by lowing off the spent ore with a current of gas.

-5. A process for extracting metalv 'from ores that includes forcibly introducing' metal carrying ore into a body of molten metal heavier than theore at apoint below its upper surface, removing from the molten metal surface any scum accumulation together with ore that may be caught in such scum, returning the removedaccumulation to the ore being introduced into the body of molten metal, and removing the spent ore from the surface of the molten metal, the spent orc being removed from the surface of the molten metal by blowing it off with acuirent of gas. v

' to the ore removing from the molten returning the removed accumulation body of metal absorbing theore at a point be 6. A process for extractingfmetal from carrying-ore into a bo heavier than the ore at a point below its upper surface, removing ,from the molten lnetal surface any scum accumulation together with ore that may be caught in Such scum, returning the removed accumulation n beingintroduced into the bod;- of molten metal, and removing the spent ore from the surface of the molten metal;'1nain taining on the ore and on the upper surface of the molten .metaland its surface at thev place of introduction of the ore, an atmosphere of non-oxidlzmgfiuid.

7 A' process for extractingmetal from ores that includes forcibly introducing metal carrying ore into a body of molten metal heavier than the ore atv a point below its upper surface, removing from the molten metal surface any' scum vaccumulation together with ore that may be caught in such scum, returning t-he removed accumulation to the ore being introduced into the body of molten metal, and removing the spent ore from the surface of the molten metal; main'- talnmg on the ore and on the upper surface of the molten metal and its surface' at the place of introduction of the ore, an atmosphere of non-oxidizing fluid; the spent ore being removed from the surface of the molten metal by bein blown with a current of non-oxidizing iiui. V Y

8. A process for extracting metalfrom ores that includes reducing the metallic content of an ore to metallic state; then forcibly injecting such ore with its metallic content in finely divided form, and withl its particles relatively widely dispersed, into a body of" metal absorbing liquid at a point below the upper surface of the liquid; and maintaining on the ore during the step of reduction and up to the point of introduction into the liguid, and also on theliquid'at the place o such introduction, a `non-oxidizing at-q mosphere. l I

9. A process for extracting metal from ores that includes reducing an ore to reduce its 'metallic content to metallic state; then forcibly introducing suchl reduced ore inv finely divided form and with relativelyv widely dispersed intol a body of Imolten metal at a point'below its upper surthe upper surface face; and maintaining on of the molten metal, .and on the ore during the operations stated, )and on the surface of the metal at the point of introduction, a non-oxidizing atmosphere. l

10. A process for extracting metal from l ores that includes reducing an ore to reduce 'its metal (content tofmetallicstate; Nthen forcibly injecting such reduced orein finely divided and` relatively state into a body of molten metal heavier than the ore at-a point below the upper surits. particles widely dispersed 4face of suchgbody; maintainin on' the ore throughout the operations state and on the surface of the molten metal at the point of injection, a non-oxidizing atmosphere; and removing spent ore from themolten metal 'surface to which it has floated by blowing it olf with a current ofnon-oxidizing gas, and

thereby at the same time maintaining a nonoxidizing atmosphere on the upper surface of the molten metal. I

11. Apparatus for such i process as herein described, .including a chamber adapted to hold a body of metal absorbing liquid; means to introduce finely dividedore into the body of liquid; and means to remove spent ore from the surface of the liquid comprising a gas circulating system providedwith means to create a current of gas over the surface of the liquid. l a l I2. Apparatus for such a process as herein described, including a chamber adaptedto hold a body ofv metal absorbing liquid; means to introduce finely divided ore into the body of liquid; and means to remove spent ore from the surface of the liquid, comprising a movin gas jet pipe movable over the .surface o supply the pipe with gas'under pressure,

and means lto exhaust from the upper part of the chamber the dust raised/by these jets.

13. Apparatus for a process such as herein described, embodying Va chamber adapted to hold a bodyA of molten rmetal of greater specific gravity than the ore being treated; means to 1 introduce ore into the. body of molten metal; means to remove any scum from the surface of the molten metal thereby t to keep the `surface. clean andxallow spent ore to rise Vthrough the surface and float thereon vand means to blow the ore from the surface of the molten metal.

14. Apparatus for a process such as herein described, embodying a chamber adapted to hod a body of' molten metal,y of greater sp cilic gravity than the ore being treated; lmeans to introduceore i'nto the body of molten metal; means .to remove any scum from the surface of the molten metal thereby to keep the surface clean and allow spent ore to rise through the surface Vand float thereon; comprisin a rotating skimmer moving over the sur ace of the molten metal, l

and a conveyor to take away the accumulation gathered Abythe skimmer; and means to'blow the spent ore from the surface of f the molten metal, comprising arotating jet pipe above the molten metal surface, means to feed gas under pressure to the jet pipe, and an outlet means from the container above the molten metal level.

15. 'Apparatus for a process such as herein described, embodying acontainer adapted to hold a body of4 metal absorbing liquid heavier than the ore being treated, means to introduce ore'in finely divided form into the the liquid, means to .an ore feed pipe leading down liquid body, and means to remove spent ore vfrom the liquid surface, comprising a blower having its intake connected to the container above the liquid level, and a jet pipe ai'- ranged in the container above the liquid level, eonnected to the outlet of the blower,

and adapted to direct a gas jet downwardly onto the liquid surface.

16. Apparatus for a process such as herein described, embodying a container adapted 'to hold a body of metal absorbing liquid heavier than the ore being treated, means to introduce ore in finely divided form into the liquid body, and means to remove spent ore from the liquid surface, comprising a blower havingits intake connected to the container above the liquid level, and a jet pipe arranged in the container above the liquid level, connectedto the outlet of the blower,

-tand adapted to direct `a gas jet downwardly tainer above the liquid level, and a pluralityA gas jet pipes rotatable in a horizontal of pla e above the liquid level and havi g jet orifices directed downwardly onto the i uid.

\ 18. Apparatus for a process of, the ind herein described, embodying a container adapted to hold a body of metal absorbing liquid heavier than the orebeing treated; throughthe center 4of the container 'to-a point near its bottom, a centrifugal runner located in aP horizontal plane at the bottom of the fcon- 'tainer and-fed from the ore feed pipe; a revolvingv skimmer adapted to remove any scum from the surface.V 4of the liquid body ore entrapped and and to remove with it any ai feeder deliveringtlle.accumulation of the skimmer into the centraly ore feed pipe.

19.` Apparatus for a .process of the kind herein described, embodying a' container" adapted a body ofmetal absorbing liquidv heavier thanthe `ore being, treated;

bottom, la cent 'fugal runner locatedy in a horizontal pl Jat @the bottom of the'container andl fed from `the ore yfeed pipe; a" revolving skimmer Vadapted to remove any scum from the surface of yan ore'feed pipe leading down through the .center of the container to a point nearits the liquid body i and to remove with it any ore entrapped" therein, and a' feeder delivering the accumulation of the skimmer into the central ore center of the feed ipe; a in a orizontal plane over the surface of the liquid body, sure to the jet pipes, and an outlet from the container above the level of the liquid body.

20. Apparatus for a process ofthe kind herein described, embed g a container adapted to hold a body of metal absorbing liquid heavier than the ore being treated; an ore feed pipe leading down through the container to a point near its bottom, a centrifugal runner located in a horizontal plane at the bottom of the eon. tainer and fed from the ore feed pipe; a

revolving skimmer adapted to remove any scum from the surface of the liquid body and to remove with it any ore entrapped and a feeder delivering the accumulation of the skimmer into the central ore feed pipe and u muller at the lower end of the ore feed 21. Apparatus for orocess of the kind herein described em ying a container adapted to hold a body of metal absorbing liquld heavier than the ore being treated, an ore feed pipe leading down into the conl tainer to a point near its bottom; a muller in said feed pipe' means located below the muller and near e bottom of the container 3o to eject ore into the body of liquid; an ore plurality of jet pipes revoluble means to feed gas under presv adapted to hold a body of metal absorbinri liquid heavier than the ore being treate an ore feed pipe leading down into the container to a point near its bottom; a mullerfin v sald feed pipe; means located vbelow the r muller and n ear the bottom of the container to eject ore into the body of liquid; an ore disturbing and feeding device feeding into the upper end of the ore feed pipe, and means to circulate the liquid from the container into the ore raising and feeding device at a int somewhat removed from its discharge into vthe ore feed pipe; means to skim the surface of the liquid body and to return the skimmed matter into the ore feed pipe; and means to blow spent ore from the surface of the Aliquid body.

In witness that I claim the foregoinv I have hereunto subscribed my name this th day of May 1923.

HARMON N. TRACY. 

